<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="d1">div</div>
<h2 class="c1">h2</h2>
<p class="c1">p</p>
<span class="c1">span</span>
<ul>
    <li>刘备</li>
    <li>关羽</li>
    <li>张飞</li>
</ul>
<!--引入jQuery框架-->
<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
<script>
    $
//let d=document.getElementById("d1");
//d.innerText="内容被修改了";
//得到id为d1的元素对象并修改文本内容为xxx
    $("#d1").text("内容被修改了");

//找到class值为1的元素并全部修改文本为xxx
    $(".c1").text("我是c1");


</script>

</body>
</html>